Composite paper and plastic yarn



Oct. 31, 1967 M. 1. PORT ETAL COMPOSlTE PAPER AND PLASTIC YARN Filed March 11, 1965 Ri e WEB Sum/v6 [5 lb Nqcwms X x W .G A]. I 7

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'INVENTORS N09701:! Pow- Anna Ye) United States Patent 3,349,552 COMPOSITE PAPER AND PLASTIC YARN Morton I. Port, West End, N.J., and William J. Hogg, Hazlehurst, Ga., assignors to Patchogue-Plymouth Company, Scarsdale, N.Y., a joint venture Filed Mar. 11, 1965, Ser. No. 438,969 8 Claims. (Cl. 57-31) ABSTRACT OF THE DISCLOSURE A composite yarn formed by intertwisting a paper yarn having a low level of elongation with a synthetic yarn formed by a thermoplastic polymer material having in the undrawn state a relatively high level of elongation, the synthetic yarn being drawn to an elongation level substantially matching that of said paper yarn to orient said synthetic yarn whereby the resultant composite has a relatively low elongation coupled with a relatively high tensile strength.

This invention relates generally to strands and cordage, and more particularly to a composite yarn formed of intertwitsed ribbons of paper and synthetic plastic material, and having physical properties which are distinctly superior to either of these materials taken alone.

In manufacturing paper yarn, the preferred practice is to convey a broad web of kraft paper drawn from a supply roll into a cutting mechanism which slits the web into individual ribbons. The ribbons then pass through spreaders into a multiple-spindle twister wherein each of the flat ribbons is twisted into a yarn having a round cross-section.

The tensile strength of paper yarn, that is to say its breaking strength under tension expressed in force per unit area of cross-section of the original specimen, is relatively poor. On the other hand, the elongation of the paper yarn, which is expressed in termsof its percentage of deformation in the direction of the load caused by a tensile force, is quite low. Thus paper yarn is characterized by low tensile strength and low elongation.

Polypropylene, polyethylene, nylon, vinyl and other forms of thermoplastic yarns are generally produced in fiber form by an extrusion process. The extruded fiber may be in ribbon, round or in other forms. Such yarns, in contradistinction to paper yarn, have good tensile strength but relatively high elongation properties. For example, polyethylene fibers have a dry tensile strength for a lowdensity type which runs as high as 27,000 psi, and for high-density types, as high as 86,000 p.s.i. However, the elongation of the undrawn fiber lies between 250% to 500%. Moreover, plastic yarns are subject to a high order of shrinkage. Thus, in the case of polyethylene yarn, the percentage of shrinkage in boiling water goes as high as 80%. Thermoplastic yarns being hydrophobic inhibit adhesion by water systems.

Accordingly, it is the main object of this invention to provide a composite yarn formed of intertwisted paper ribbon and plastic yarn, the properties of the composite yarn being superior to either material considered separately.

More specifically, it is an object of the invention to provide a composite yarn of this type wherein the plastic yarn is drawn to a degree at which its elongation substantially matches that of the paper ribbon, the resultant composite having a relatively low elongation coupled with a relatively high tensile strength.

Also an object of the invention is to provide a composite yarn of the above type having an exceptionally low percentage of shrinkage.

A significant advantage of the invention resides in the fact that the composite yarn is suitable for use in prelroll 17, the stretched 'ice paring cops and bobbins for insertion in weaving shuttles, whereas pure plastic ribbon yarn because of its stiifness and smoothness, cannot be copped etficiently. The composite yarn is also useable in fabricating woven carpents, as chain yarn, stutter yarn, and Axminster yarn, as well as being a satisfactory tufting medium for tufted fabrics and carpets. It is also useable in twine and cordage ap plications in place of conventional hemp, paper or cotton.

Another important advantage of the invention lies in the fact that the composite yarn has good adhesion properties, for even though the plastic component is hydrophobic, the paper component is not.

For a better understanding of the invention, as Well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein the single figure shows schematically a system for producing a composite twisted yarn in accordance with the invention.

Referring now to the figure, there is shown a system for producing a composite paper and plastic yarn comprising a source 10 of plastic yarn PL, which may be in ribbon or-other form, and a source 11 of paper ribbon PA. The plastic yarn, which is shown wound on a supply package, is in the form of an extruded undrawn polypropylene or polyethylene material.

It is to be understood that the invention is useable with other forms of thermoplastic material, including those mentioned previously, made by any known extrusion or other fiber-forming process, which material can be hot or cold drawn to enhance its tensile properties and which can be drawn to a level of elongation substantially matching that of the paper component in the composite yarn.

The undrawn plastic yarn from the supply package 10, shown in ribbon form, is conducted through suitable guides 12 and 13 into feed rolls 14 and 15. From the feed rolls, the yarn is looped over a drawpin 16, and then wrappe-d'several times around a draw roll 17, the wraps being kept apart by a separator roll 18. From the draw yarn goes into the ring twister, to be later described.

Draw roll 17 is driven by means of a motor 19, the roll being mechanically coupled by a suitable gear reduction train to feed rolls 14 and 15, whereby the yarn may be stretched to several times its original length. Drawing, which takes place between drawpin 16 and draw roll 17, acts to orient the molecular structure of the ribbon and thereby increase its strength and recoverable extensibility. A number of wraps around the draw roll is required to prevent slippage of the ribbon and in practice, the axis of separator roll 18 is inclined slightly relative to the draw roll to keep the wraps apart. The draw ratio is that between the peripheral speed of the draw and feed rolls. If desired, heat may be supplied to the drawing point to effect hot drawing, thereby lowering the drawing load more than the breaking load to enable a greater draw ratio to be achieved.

The draw ratio is adjusted so that for a given ribbon material, the resultant elongation of the plastic ribbon substantially matches that of the paper ribbon. For example, if the paper ribbon has an elongation of three percent, and the undrawn plastic ribbon an elongation of 50%, the plastic is drawn so that it then possesses an elongation of about 5%. One must be careful not to come too close to the break point of the plastic ribbon, particularly in high-speed operations.

While the drawing shows the ribbon PL being taken from a package, in practice it is possible to conduct the ribbon directly from the extruder to the drawing mechanism, thereby making the process continuous.

The machine 11 for slitting a paper web into paper ribbons is preferably of the type disclosed in Patent 3,111,000 of Sain and Hogg (Nov. 19, 1963). In this patent, the broad web of paper is fed into a cutter section and slit into ribbons, the ribbons being spread for conveyance into a twister. Each paper ribbon goes through a guide or ring 20 into a twister 21. The twister may be of any ring or fiyer-type, such as that shown in the Sain and Hogg patent, or any other form of twister machine in commercial use.

Also fed into the ring 20 to be twisted simultaneously with the pape ribbon PA, is the drawn plastic ribbon PL, the two ribbons being intertwisted to form the composite yarn PA-PL. This composite yarn, which is composed of plastic and paper ribbons, having matching elongations, is characterized by high tensile strength. While thermoplastic yarn exhibits excessive shrinkage, when in composite form the yarn shrinkage, which is restrained by the paper component, is reduced to a nominal amount. In practice, where the paper ribbon passes through a folding device before it is twisted, the plastic yarn may be introduced into the folder rather than directly into the twister.

The surface of the composite yarn is far less smooth than a pure plastic yarn, hence the composite yarn lends itself to many uses for which plastic yarn is not suitable, such as use requiring adhesion.

While there have been shown and described a preferred composite paper and plastic yarn and a machine for fabricating same, in accordance with the invention, it will be appreciated that many changes and modifications may be made therein without, however, departing from the essential spirit of the invention as defined in the annexed claims.

What we claim is:

1. A machine for manufacturing composite yarn of high tensile strength and low elongation, comprising:

(a) a cutter to slit a web of paper into ribbons,

(b) a twister to twist each ribbon from said cutter into a yarn,

(c) means to draw a thermoplastic yarn to produce an oriented yarn whose elongation substantially matches that of said paper ribbon, and

(d) means feeding said oriented yarn into said twister with said paper ribbon to intertwist therewith and thereby form said composite yarn,

2. A composite yarn comprising:

(a) a paper yarn having relatively low elongation and low tensile strength, and

(b) a synthetic yarn intertwisted with said paper yarn,

said synthetic yarn being formed from a thermoplastic polymer material which in the undrawn and unoriented state has a relatively high level of elongation said synthetic yarn being in a drawn and oriented state wherein its level of elongation substantially matches that of said paper yarn and wherein it has a high tensile strength, whereby the composite yarn has low elongation coupled with relatively high tensile strength.

3. A composite yarn as set forth in claim 2, wherein said synthetic yarn is formed of polyethylene material.

4. A composite yarn as set forth in claim 2, wherein said synthetic yarn is formed of polypropylene.

5. A composite yarn as set forth in claim 2, wherein said synthetic yarn is formed of nylon.

6. A composite yarn as set forth in claim 2, wherein said synthetic yarn is formed of vinyl.

7. The method of forming a composite yarn of high tensile strength and low elongation, comprising the steps of drawing a thermoplastic yarn to an extent wherein its elongation substantially matches the elongation characteristic of a paper ribbon, whereby said plastic yarn is oriented, and intertwisting the oriented. plastic yarn and paper ribbon to produce said composite yarn.

8. The method of forming a composite yarn of high tensile strength and low elongation, comprising the steps of cutting a broad web of paper into ribbons, passing each ribbon into a twister mechanism, and simultaneously feeding into said twister mechanism a thermoplastic yarn of a material which is drawn to an elongation substantially matching the elongation of said paper ribbon.

References Cited UNITED STATES PATENTS 2,729,055 1/1956 Tobias 57-154 2,832,190 4/1958 Bacon 57-151 2,981,052 4/1961 MacHenry 57-31 X FRANK J. COHEN, Primary Examiner.

W. S. BURDEN, Examiner, 

1. A MACHINE FOR MANUFACTURING COMPOSITE YARN OF HIGH TENSILE STRENGTH AND LOW ELONGATION, COMPRISING: (A) A CUTTER TO SLIT A WEB OF PAPER INTO RIBBONS, (B) A TWISTER TO TWIST EACH RIBBON FROM SAID CUTTER INTO A YARN, (C) MEANS TO DRAW THERMOPLASTIC YARN TO PRODUCE AN ORIENTED YARN WHOSE ELONGATION SUBSTANTIALLY MATCHES THAT OF SAID PAPER RIBBON, AND (D) MEANS FEEDING SAID ORIENTED YARN INTO SAID TWISTER WITH SAID PAPER RIBBON TO INTERTWIST THEREWITH AND THEREBY FORM SAID COMPOSITE YARN. 